I’ve got a house, 1970s ranch, with blow-in insulation in the attic. We’re in Zone 9, CA central coast. In most parts of the house the insulation rocks: it’s 100F outside, the house stays quite cool until quite late in the day, and we might turn on the A/C around 5pm or later.
But in certain parts of the house, the house heats up. I was just up in the attic today, and inspected some of these areas, and the blow-in insulation was not that deep or missing in some places. Not surprisingly, these areas were furthest from the attic access, so the insulation installer probably had difficulty cover those areas.
Question: how should I upgrade that problem insulation? Blow in more loose stuff, or add bats of insulation? If I add bats, do I need to remove the old blow-in?
Also, in the areas of the house that are heating up, how do I identify the heat source? e.g., is it inadequate wall, v. ceiling insulation? Is there a set of IR goggles that will just show the hot spots?
Since the rest of the attic uses blown-in insulation, it would probably be much easier to just blow in more where needed. Otherwise, you’ll have to remove it where ever you want to use batted rolls.
Just use an IR thermometer to find hot spots. IR goggles would be very expensive but IR thermometers (they look like a 20’s style death ray of sorts) have become very common and are getting cheap.
Another thought: it seems like bats would be cheaper, in that I can just buy some bats and place them in the attic, where for blow-in I’d have to hire someone. No?
bats cheaper? No way. Blow in is a heck of a lot cheaper. And the big box stores will rent you the blower for cheap with the purchase of some number of blow in bags. Dollars to R value blow in is cheaper. It’s easy to do yourself, but messy. Wear a mask. Be prepared to get hot and sweaty.
That one looks almost exactly like mine. I’ve seen them as cheap as $39.99 but features and accuracy vary. For the purposes you have in mind, any of them will do.
First build a walkway the length of the attic with 2x4’s on edge 18" apart, covered with 3/8 plywood 18" x 48", screwed on top with sheet rock screws. The cavity was also filled with roll insulation.
Next fill in any bare and really low areas with bagged insulation.
I’ll second that.
The walkway also provides service access to the lighting relay system installed when the house was built.
Then using rolled (unfaced) insulation roll it ACROSS the joists and push it to the eaves without blocking ventilation at the eaves. I used a farmer’s hay fork to push the next roll tight against the first and so on across the entire attic area.
Wear a dust mask, vinyl gloves, and a long sleeve shirt when working with the insulation.
Be careful to not step thru the ceiling!
OK, I think I’ll just roll bats over the blown in stuff as suggested. Thanks for the methodology.
It’s a relatively small area that needs more coverage, probably 35x35. But it’s a hard area to get to and probably 70’ from the attic hatch. It takes me at least 5 minutes of joist-dancing to get there from the hatch, esp. on a narrow section btw a skylight and a cathedral cieling. It’s gonna be a real bear dragging all of those bats to thier destination.